Intra- and Inter-Observer Reliability of Two Common Radiographic Methods of Carpal Height Measurement

Carpal height is a radiographic ratio with clinical significance in rheumatologic diseases and Kienbock disease, which is measured with different methods. The purpose of this study was to assess the two popular methods of measurement of this angle with respect to inter- and intra-observer variability.Good quality photographs were made of ten radiographs and two experienced orthopedists, in two separate occasions measured the length of third metacarpal bone, the longest length of capitates, and the distance between the base of third metacarpal bone and the articular surface of the radius. The remainder of the calculations was made by computer.Intra-observer reliability of the Youm and Nattrass ratios were calculated as “high” and “fair”, respectively. With regard to inter-observer reliability, the accuracies of both indices were poor. Intra- and inter-observer agreement for detection of wrist collapse was “substantial” for Youm ratio and “fair to moderate” for Nattrass ratio. The ratios had poor agreement with each other, in regard to detection of collapse of the wrist joint.Although neither of the ratios had perfect or high reliability with regard to the subject of the study, it seems that the accuracy of Youm index is higher than the other method.